


Obscenity

by SocialDegenerate



Series: Vincent and Diedrich's Adventures in Debauchery [2]
Category: Kuroshitsuji | Black Butler
Genre: Aftercare, Anal Sex, Come Eating, Creampie, Cunnilingus, Dom/sub, Established Relationship, F/M, Hair-pulling, M/M, Multi, Plot What Plot/Porn Without Plot, Polyamory, Rough Sex, Threesome - F/M/M, Vaginal Sex
Language: English
Status: Completed
Published: 2016-09-28
Updated: 2016-09-28
Packaged: 2018-08-18 08:33:51
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,224
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8155811
Author URL: https://archiveofourown.org/users/SocialDegenerate/pseuds/SocialDegenerate
Summary: Vincent and Rachel double-team their loyal German dog

  
    “What do you think, my love?” Vincent asked as he turned his attention back to Rachel, his hand moving from her face to gather her hair and pull it forward over one shoulder. Diedrich swallowed hard as her entire naked back was revealed, his trousers beginning to feel uncomfortably tight. “Should he be rewarded despite his tardiness?”





	

**Author's Note:**

> This happened way too easily, largely thanks to the beautiful comments on Depravity from aperfectdevil and viscountofperv, plus the encouragement of a third party who shall remain nameless but who knows what they did. It's technically a prequel to Depravity rather than a sequel, but the only way to tell is that Rachel is pregnant in Depravity, yet she's neither pregnant nor a mother here.
> 
> The general assumption here is that these three are so established, they are all already well aware of their limits and rules of engagement; so any negotiation happens offscreen. Both Rachel and Vincent willingly participate in their open marriage and are healthily polyamorous.

Diedrich was speaking to Chlaus when he got the sudden feeling that someone was watching him, and he had a sneaking suspicion that he knew who it was. Still nodding in agreement with whatever Chlaus was saying, Diedrich glanced to the side at where Vincent was lounging in his usual chair, his eyes dark and hooded as he stared back at Diedrich.

Part of Diedrich prickled at the lazily crooked finger beckoning him over, and had it been anyone but Vincent on the other side of the room, he would have spat in their face and left at being treated so demeaningly. As it was, though, Diedrich simply took his time in making his excuses to Chlaus before eventually dawdling his way over to Vincent, sitting in the chair beside him with a vaguely irritated look on his face.

The smile that Vincent gave him in return was perfectly pleasant, but his eyes promised something that had Diedrich’s gut rolling. He and Vincent had a very strict understanding about Vincent _not_ putting him on his knees in front of the other Aristocrats, and although Diedrich knew that Vincent wouldn’t try anything right there and then, the thought that he _could have_ had an exciting mix of mortification and excitement running through Diedrich’s system.

The _idea_ of being demeaned in front of the others was arousing; Diedrich didn’t think that the reality- and its consequences- would be anywhere near as nice. Thankfully, for as much of a bastard as Vincent could be at the best of times, he seemed to realise that Diedrich would leave forever without a backwards glance should he purposefully overstep the agreed-upon limits.

“I am getting bored,” Vincent said quietly, leaning in close and _very obviously_ aware of the effect he was having on Diedrich. “I think I might go and fuck my wife.”

He said it as casually as one might propose going to read a book, and Diedrich had to hold back a pleasant little shudder. Vincent and Rachel made an uncomfortably beautiful couple, a husband and wife alike in sexual appetite and depravity.

“What about…?” Diedrich asked, gesturing to the other Aristocrats around the room. His voice was a little hoarse and Vincent smirked as he clapped a hand on Diedrich’s shoulder. The gesture would have looked like camaraderie to anyone else, but Diedrich could feel strong fingers biting uncomfortably into his skin, and this time he couldn’t restrain his shudder.

“I trust you to get rid of them without raising anyone’s ire,” Vincent said lightly with a bright smile that crinkled his eyes. Diedrich opened his mouth to argue but he _couldn’t_ ; he was just too weak for that goddamn face.

Years of military experience and he still couldn’t say no to a prissy, over-privileged noble. He was a disgrace to his family name.

“Fine,” Diedrich ground out, clenching his fists more at his own weakness than at Vincent.

“Good boy,” Vincent murmured, too quietly for anyone else to hear, and Diedrich’s face burnt in shameful pleasure. “Be quick about it and Rachel might just let you join us.”

A jolt of arousal had Diedrich’s groin muscles tightening, and Vincent squeezed his shoulder even tighter for a second before letting go. Diedrich watched him stand and leave the room, effortlessly sidestepping the other Aristocrats’ efforts at conversation with a genuinely kind smile and zero indications about where he was actually going. The man really was a force to be reckoned with, and Diedrich had to admit he was a little jealous about the way Vincent easily navigated both London’s high society and its criminal underworld.

Shaking his head at Vincent’s audacity, Diedrich stood up and immediately set to clearing the manor of its guests. Thankfully that evening had simply been a meeting of the Aristocrats rather than a full-blown party, and most of the group gratefully took Diedrich’s hints that they may have had other business to attend to.

But no matter how many openings he gave Undertaker to leave, it seemed like the creepy mortician just wanted to chat. He supposed that being surrounded by dead bodies all day might leave a man wanting for human interaction, but _most_ people were able to pick up on the clues that their presence was becoming unwelcome, and didn’t persist in idle smalltalk that served no real purpose when they were the last guest left at a gathering.

Diedrich was uncomfortably aware of the passing time as Undertaker continued to blather on, and he was one more subject change away from physically throwing the man from the manor when Undertaker suddenly went silent mid-sentence.

“Ah, but I should return to my own guests,” Undertaker said, his hair hiding most of his expression from Diedrich’s eyes. “They might be getting up to mischief while I’m gone.”

Diedrich barely managed to cover his disgust; Undertaker set him on edge something fierce, and the way he spoke about his corpses was positively abhorrent.

“Good night,” Diedrich managed to say somewhat normally, trying for subtle as he ushered Undertaker towards the door. Thankfully the man was _finally_ happy to take a hint, and he only paused to linger once in the doorway.

“Bye bye, Baron,” Undertaker said, his face splitting into a manically wide smile. “I hope you have a... _pleasurable_ evening.”

Disappearing in a swirl of loose black clothes and long hair, Undertaker fled the manor, his hysterical laughter echoing behind him. Diedrich had a sinking suspicion that Undertaker _knew_ , but he forced himself to believe that such a thing was impossible. People always put he and Vincent’s close relationship down to how long they’d known each other, even if Diedrich was a known bachelor and Vincent was a known deviant.

Heaving a relieved sigh, Diedrich made a quick path for Vincent’s bedroom. Rachel had her own quarters, but Diedrich knew from experience that they were more often than not to be found in Vincent’s bed. Rachel’s bed, on the other hand, was kept clean and fresh should the lady of the house wish to sleep in a room that didn’t smell of sex, or should she- on rare occasions- desire some time away from her sexually voracious husband.

Still, the two shared a bed more often than any other noble couple that Diedrich knew, their marriage one of both political benefit _and_ love. Their closeness would have made Diedrich uncomfortable to get between them, had he not been well aware of the fact that they both eagerly welcomed him.

Diedrich had often wondered if the open nature of their marriage contributed to their persisting love, but he would never really know. Vincent had never struck him as a particularly monogamous figure, even as a teenager, and he was certainly pleased by Rachel’s eager participation in their _arrangement,_ so Diedrich figured that they had stumbled into the best possible scenario for the both of them.

Diedrich, for one, wasn’t about to complain; Vincent’s marriage had worried him at first, until he’d learnt that it truly wouldn’t change anything for the worse.

Coming to a halt in front of Vincent’s closed bedroom door, Diedrich took a deep breath and knocked, waiting with worried anticipation as he listened closely for a sign to enter. His shoulders relaxed when Vincent called to him, and he opened the door only for his mouth to suddenly run dry.

Vincent was lounging back on the opulent bed like the hedonistic noble he was, Rachel’s naked back exposed to Diedrich’s eyes as she writhed and ground on his lap. One of his hands was splayed on the small of her back, right below the ends of her loose hair, and the other was lovingly cupping her face, his smile to her fond and indulgent.

The expression was gone by the time that Vincent lazily turned his head to look at Diedrich, an unimpressed eyebrow arching high as he frowned. “Did I not say to be quick about it, Diedrich?”

“I apologise,” Diedrich forced out resentfully, forcing himself not to break eye contact. “Undertaker was-”

“I do not care,” Vincent interrupted dismissively, his hand starting to stroke slightly at the soft skin of Rachel’s lower back. She hadn’t gone still in his lap but she also wasn’t moving particularly quickly, and even if Diedrich wasn’t quite as interested in women as Vincent was, he was still entranced by her sensual motions.

It was hard to tell if Vincent was truly annoyed or if he was just playing one of his games, and Diedrich shifted a little as he waited for a clue as to which one it was. There was an almost equal chance that Vincent would either send him away or allow him to remain, and Diedrich was desperately hoping for the latter.

“What do you think, my love?” Vincent asked as he turned his attention back to Rachel, his hand moving from her face to gather her hair and pull it forward over one shoulder. Diedrich swallowed hard as her entire naked back was revealed, his trousers beginning to feel uncomfortably tight. “Should he be rewarded despite his tardiness?”

Rachel looked over her shoulder at Diedrich, a pretty flush on her high cheekbones, and she pursed her lips in contemplation. Turning back to Vincent, she leaned in to whisper something in his ear, and Vincent’s sudden, loud laugh almost made Diedrich jump.

“I do _so_ love the way you think,” Vincent said, and Diedrich was left in limbo as he watched the pair kiss, deep and slow. By the time they pulled apart, Diedrich was completely hard in his trousers, his cock throbbing with need as he forced himself not to let his hands wander anywhere close.

“Oh, you’re still here,” Vincent said as he looked back up at Diedrich, feigning surprise. Diedrich glared at him for a few seconds before remembering that he was trying to win back Vincent’s favour, and he settled into a more neutral expression. “Well, as you might be able to tell, we are already getting close to finishing up here.”

To drive his point home, Vincent thrust his hips up, making Rachel moan as her body moved on his cock. He smirked at Diedrich and repeated the motion, Rachel beginning to move quicker again on top of him. “She is not going to allow me to waste any more time dealing with you.”

Diedrich was left to watch as they began to properly fuck again, Rachel bouncing in Vincent’s lap as he pinched and pulled at one of her nipples. About to resign himself to enjoying nothing but his own hand back at his accommodations, Diedrich turned to leave when Vincent’s clear command broke through Rachel’s pleasured moans.

“ _Kneel_.”

Diedrich had turned back around and was on the floor before he knew it, and a tiny part of his arousal-addled brain wondered when he’d become such a well trained dog. Vincent’s voice seemed perfectly attuned to something shameful inside of him, some part of him that desperately wanted to be dominated and controlled, and he couldn’t resist the call.

“Close the door,” Rachel said between pants with a quick glance over her shoulder, “unless you wish to give the staff a show.”

Groping blindly behind him for the door he’d left open, Diedrich didn’t take his eyes off the entrancing sight before him as he finally managed to get the door closed. It was selfish, but he felt like he’d _earned_ the privilege to watch Vincent and Rachel, and he didn’t want anyone else to receive the same reward right then.

It wouldn’t have been the first time that Diedrich had looked up in a post-orgasmic haze, just to see a gaggle of servants crowding around the doorway. In the Phantomhive Manor, closed doors demanded privacy, but open ones were fair game.

Diedrich was finding it increasingly harder to avoid even simply adjusting his uncomfortable dick as Rachel continued to ride her husband, her moans reaching a crescendo as she shook and came on top of Vincent. He was murmuring faint praise and words of love as she fell apart, and Diedrich could see him being unbearably gentle and tender with her slackened body as he chased his own pleasure.

Sometimes he wished that Vincent would be that kind to him; but then the darkness inside of him reared up in protest, and Diedrich remembered just why he kept returning to submit to Vincent’s every whim.

No one else would understand what he needed, what he’d come to love and crave as much as he fought against it.

Vincent’s low groan told Diedrich that he was finishing inside Rachel, and she sighed happily at the feeling in a way that had Diedrich burning with jealousy. He wasn’t jealous of _her_ , per se, but he wanted to feel as good as she was obviously feeling.

As Diedrich watched, Vincent lifted her off him and placed her flat on the bed beside him, cupping her face and kissing her as her limp legs spread open. The light in the room was enough for Diedrich to be able to see the come and slick glistening across her pussy and thighs, and he licked dry lips at the enticing sight.

“I cannot sleep like this,” Rachel said, lifting herself up onto her elbows to look first at Vincent, and then at Diedrich. “I need to be cleaned up.”

As much as he wanted to rush to the bed, Diedrich waited for Vincent or Rachel to explicitly call him before moving.

“Stand up,” Vincent ordered, before he went back to his wife. “Would you like him naked, or would you prefer to ruin his uniform?”

Diedrich almost protested before he caught himself, knowing that arguing would just make them ruin his clothes out of pure spite. Vincent paid handsomely to immediately replace anything he dirtied beyond repair, but it was still mortifying to have people wondering why Diedrich’s uniforms needed to be replaced so often.

Rachel thought for a moment, and Diedrich was unbearably relieved when she commanded him to undress. He wasn’t quite as compelled by her voice as he was by Vincent’s, but the easiest way to please Vincent was to do whatever his beloved wife wished, and so Diedrich obeyed her orders as if they were Vincent’s own.

The room was cool without any clothing on, but his aching erection didn’t abate at all from the chill, and Diedrich could feel two pairs of eyes scrutinising every inch of his body. He knew that he had nothing to be self-conscious about, his form tall and athletically toned, and yet he still felt the irrational urge to cover himself.

“Clean me up, Diedrich,” Rachel said, gesturing to the slick mess beginning to leak from her pussy. “ _Before_ it gets on the sheets, if you please.”

Crossing the room in long steps, Diedrich hid a smirk as an idea occurred to him, something that made his heart beat fast in his chest. After climbing onto the bed, he began to kneel between Rachel’s legs, only to pause before leaning forward to put his mouth to her. Looking to Vincent beside him, Diedrich tried his best to let hesitation show on his face, and his cock twitched in excitement as Vincent rolled his eyes.

Diedrich gasped quietly when Vincent quite literally grabbed him by the scruff of his neck, fingers digging painfully into the sides of his throat as Vincent dragged Diedrich’s face closer to his own mouth.

“Do not think that I am unaware of what you are doing,” Vincent said in a low voice that rumbled dangerously. Diedrich barely had time to process the statement when Vincent shoved him forward, pushing until Diedrich was panting with excitement against Rachel’s pussy and his arms were trapped beneath his torso. The first long lick he took tasted of both Rachel and Vincent, and Diedrich eagerly swallowed before going back for more.

Rachel’s squeal of approval was met by Vincent’s dark laugh, and Diedrich felt Vincent press up against his ass and drape over his back even as he still maintained an iron grip on Diedrich’s nape.

“Good, Dee. If you can pleasure my wife the way that she deserves, we _might_ consider not sending you away immediately afterwards.” Still pushing Diedrich forward so that his cheeks, lips and chin quickly became soaked in come and slick, Vincent hummed happily when Diedrich pushed his tongue inside Rachel, pulling come from the hole that was still loosened by arousal and Vincent’s cock.

Knowing the way that they both liked it, Diedrich let himself make loud, sloppy noises, sucking and licking all evidence of mutual orgasm from Rachel’s body. As he worked, he could feel Vincent’s cock reawakening against his ass, and he wasn’t all that surprised when Vincent’s hand and weight disappeared, only to be replaced by slick fingers rubbing across his asshole.

Determined not to let Vincent distract him from his task, Diedrich redoubled his efforts until he was _sure_ that all of Vincent’s come was gone, although he immediately missed the taste. Without Vincent in the way, Rachel’s thighs had clamped themselves around Diedrich’s head, although she lacked the strength to really squeeze; she was panting and moaning as his tongue flicked inside her, and she only got louder when he turned his attention to her clit.

She bucked against his face, and the excitement of knowing that Rachel was enjoying herself so much almost had Diedrich forgetting that Vincent was still teasing him from behind.

_Almost_.

He almost forgot how to please a lady when two of Vincent’s slick fingers suddenly shoved into him, the pleasure-pain leaving Diedrich gasping against Rachel’s wet folds and unable to properly use his tongue.

“Do you not have a _task_?” Vincent snarled, the hand back on the nape of Diedrich’s neck and rubbing his face into Rachel even as a third finger pushed into his unprepared asshole. Diedrich was sure that the slightest friction on his cock in that instant would have made him come, and he struggled to keep himself under control while trying to lick and suck at Rachel’s clit.

If he came before Rachel and Vincent said he could, there would be trouble; and it wouldn’t be the _good_ kind. Still gasping to catch his breath, Diedrich put as much focus as he could into working Rachel’s clit, and he nearly collapsed with relief when she grabbed his hair hard and _yelled_.

Her hips humped against his face as she used him for her own pleasure, her come pulsing out of her and onto Diedrich’s face. When her hand fell away from his hair and her legs from his head, Vincent pulled him up by the neck, and Diedrich finally took the chance to free his arms and hold himself up, his head dropping forward when Vincent let him go.

He barely got to regain his breath before the head of Vincent’s cock was pushing at his hole, his eyes going wide when the thick length began to stretch and fill his ass. When Vincent was all the way inside, he suddenly stopped and leaned closer to Diedrich’s ear. “Ask Rachel if she will allow you to pleasure her again.”

“Countess,” Diedrich gasped, lifting his head enough to meet Rachel’s hungry gaze, “may I pleasure you again?”

“...You may,” Rachel said eventually after she sat up against the bedhead, once again knotting her fingers into Diedrich’s hair. She didn’t pull as harshly as Vincent usually did, but Diedrich relished the sting regardless and let her guide him back to the heat between her legs. Vincent still hadn’t begun to move inside him, but Diedrich shuddered violently when nimble fingers began to caress his balls.

“I am going to fuck you,” Vincent announced, still playing with Diedrich’s balls. “If you are not pleasing Rachel properly, she will tell me and I will stop. You will _not_ come before she does.”

Suddenly, those teasing fingers gripped tight, and Diedrich yelled with pain before Rachel muffled the noise with her pussy. Still, even though his erection flagged a little from the pain, excitement left Diedrich shaking, and he once again began to eagerly lap at Rachel’s pussy. Her happy noises seemed to meet Vincent’s strict standards, and he let up on Diedrich’s balls before grabbing his hips tight and beginning to fuck him in earnest.

There was no gentle build-up, and Diedrich was forced to quickly adapt to Vincent’s rhythm so that he didn’t miss a beat in eating Rachel out. The feeling of Vincent harshly fucking him, rubbing against the spot that left him weak more often than not, had Diedrich struggling to stay in control of his long-ignored cock, and he tried to distract himself with Rachel’s pleasure.

His head hurt where Rachel was tugging on his hair and his hips hurt where Vincent’s fingers were holding him tight, and Diedrich felt like he was going to lose his mind. His entire existence had narrowed down to the two people using him as if he was a sex toy, and it was one of the most amazing things he had ever experienced.

Rachel and Diedrich filled the room with their moans, Vincent’s quieter noises being lost underneath the cacophony of the other two, loud to the point where Diedrich could no longer tell if Rachel was getting close to orgasm. The building pressure in his groin had him desperately hoping that she was, and an anguished tear fell from one of Diedrich’s eyes.

Overstimulation did bizarre things to him.

Just when he was getting seriously concerned that he was going to fail both Rachel and Vincent, the hand in his hair tightened until he could feel a few strands rip out, and Diedrich clamped his mouth over Rachel’s hole and drank down everything she had to give him as she writhed wildly against him.

Tentatively licking at her afterwards, Diedrich grunted when she shoved his face away, obviously too sensitive after three relatively quick orgasms to handle anything more. It was perhaps a little impudent of him to rest his face against her thigh, but she allowed it regardless, her hand still in his hair but no longer pulling as Vincent continued to fuck him.

“You did very well, Diedrich,” Rachel murmured in a quiet voice, soothing and affectionate in a sharp counterpoint to Vincent’s brutal treatment and her earlier demeanour. “You may come when you wish.”

“She told you to _come_ ,” Vincent said harshly when nothing immediately happened, punctuating the words with harsh thrusts and a quick slap across his ass. Diedrich only just managed to get his hand over the head of his cock before he was coming on command, his entire body going limp as more tears leaked out of his eyes and he shook uncontrollably.

He was fairly certain that he caught all of his come, lacking the energy to lick it off the bed should he dirty the covers; he knew what Vincent was like, and it wouldn’t have been the first time that he was made to clean up his own mess. When Rachel tugged at his bicep, he didn’t resist, and she had his hand up by her mouth before he realised what she was doing.

The feeling of Rachel’s tongue sliding all over his palm and fingers, licking up his come and making happy little noises all the while, had Diedrich gasping desperately. If Vincent’s increasingly harsh breathing was any indication, he was more than pleased by the sight, and Diedrich gasped brokenly as Vincent’s thrusts became shorter and quicker.

“ _Dee_ ,” Vincent groaned as he pulled out of Diedrich’s ass. One of the hands disappeared from Diedrich’s hip, the sounds of Vincent quickly stroking himself filling the air as Diedrich moaned into Rachel’s thigh.

Hot, wet come splattered against Diedrich’s back and his knees gave out, leaving him sprawled against the mattress as Vincent came down a little more gracefully beside him. A gentle stroking in his hair told Diedrich that Rachel was bringing them both down as they panted tiredly, and he barely managed to get his arms to work well enough to wind one around Rachel’s waist and drape the other over Vincent’s sweaty stomach.

“You were so good for us, my beautiful Diedrich,” Vincent said, voice soft as it only ever got when his games were over for the time being. “Thank you.”

Unable to form words, Diedrich just slurred something unintelligible, making Rachel’s clear, high laugh pleasantly ring out. “I will call someone to bring us something to clean up with.”

Fading in and out of consciousness, Diedrich was only vaguely aware of a servant entering the room, secure in the knowledge that the Phantomhive staff were all unfailingly discreet. He was fairly certain that it was Rachel who gently cleaned the drying come from his skin, and that the married couple then assisted each other in getting clean.

He thought that he felt lips on both cheeks at once after he was moved onto his back, with Rachel then tucking herself against his side while Vincent placed himself half on top of Diedrich, his arm stretching across to hold onto Rachel. Diedrich felt warm and loved, and the beast inside him was sated once again; he’d been used and degraded and hurt and it was _perfect_.

There was certainly something to be said for depravity.

**Author's Note:**

> [Visit me on Tumblr](http://socialdegenerate.tumblr.com)


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